Dropper - Brewing stand inconsistency

Steps to produce the bug:
1. Place a dropper facing a brewing stand
2. Place 2 hoppers: one going into the dropper and one taking items from the brewing stand (being under the brewing stand) Both hoppers are connected to a double chest on the other "door" (my english is bad, sorry)
3. Fill up the upper chest with water bottles
4. Makes the dropper fire several times with a button
5. After a while, bottles begins to not be placed into the brewing stand.

I had this problem trying to make a hard-drive-like-system using brewing stands, based on Etho's design: https://www.youtube.com/watch?v=5vgO-AWYyPw (12:40)
In the files, a screenshot of my setup. (I was blocked after 3 bottles fired)
Thanks for solving this problem

EDIT: In the attached world, i success to place two more bottles each time I exit the world and come back
2nd EDIT: This bug may be related to https://bugs.mojang.com/browse/MC-111753 , because it also implicates a brewing stand that doesn't work correctly